A Wave Phenomenon
... The matter finally appeared settled in 1801 when a British physician, Thomas Young (1773–1829), detected clear signs of wave-like behaviour. It only remained, it seemed, for those who came after to elaborate the wave model and to determine the nature of the waves. This was achieved in 1864, by Jame ...
... The matter finally appeared settled in 1801 when a British physician, Thomas Young (1773–1829), detected clear signs of wave-like behaviour. It only remained, it seemed, for those who came after to elaborate the wave model and to determine the nature of the waves. This was achieved in 1864, by Jame ...
Basics of Polarizing Microscopy
... device is the polarizer and the secondary device is the analyzer is called crossed nicols. Parallel nicols is the state in which the analyzer is rotated to make the direction of the transmitting linearly polarized light match with the polarizer, and the amount of light transmittance is maximized. (F ...
... device is the polarizer and the secondary device is the analyzer is called crossed nicols. Parallel nicols is the state in which the analyzer is rotated to make the direction of the transmitting linearly polarized light match with the polarizer, and the amount of light transmittance is maximized. (F ...
Jacaranda Physics 1 2E Chapter 2
... when it travelled from air into glass, but how? One explanation or model of light proposed that light travelled faster in glass. Another model of light proposed that light travelled slower in glass. Scientists at the time did not have the technology to measure the speed of light through materials su ...
... when it travelled from air into glass, but how? One explanation or model of light proposed that light travelled faster in glass. Another model of light proposed that light travelled slower in glass. Scientists at the time did not have the technology to measure the speed of light through materials su ...
Metalloenzyme Functions
... more abundant anaerobic oxidizing archaea (AOA) 24 hemes (irons) per molecule! What does nature actually use in the oceans if this enzyme is not present? ...
... more abundant anaerobic oxidizing archaea (AOA) 24 hemes (irons) per molecule! What does nature actually use in the oceans if this enzyme is not present? ...
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria and terrestrial invertebrates such as fireflies. In some animals, the light is produced by symbiotic organisms such as Vibrio bacteria.The principal chemical reaction in bioluminescence involves the light-emitting pigment luciferin and the enzyme luciferase, assisted by other proteins such as aequorin in some species. The enzyme catalyzes the oxidation of luciferin. In some species, the type of luciferin requires cofactors such as calcium or magnesium ions, and sometimes also the energy-carrying molecule adenosine triphosphate (ATP). In evolution, luciferins vary little: one in particular, coelenterazine, is found in nine different animal (phyla), though in some of these, the animals obtain it through their diet. Conversely, luciferases vary widely in different species. Bioluminescence has arisen over forty times in evolutionary history.Both Aristotle and Pliny the Elder mentioned that damp wood sometimes gives off a glow and many centuries later Robert Boyle showed that oxygen was involved in the process, both in wood and in glow-worms. It was not until the late nineteenth century that bioluminescence was properly investigated. The phenomenon is widely distributed among animal groups, especially in marine environments where dinoflagellates cause phosphorescence in the surface layers of water. On land it occurs in fungi, bacteria and some groups of invertebrates, including insects.The uses of bioluminescence by animals include counter-illumination camouflage, mimicry of other animals, for example to lure prey, and signalling to other individuals of the same species, such as to attract mates. In the laboratory, luciferase-based systems are used in genetic engineering and for biomedical research. Other researchers are investigating the possibility of using bioluminescent systems for street and decorative lighting, and a bioluminescent plant has been created.